| West Chicago to Olivares | 4,203.60 mi (6,765.04 km) |
| West Chicago to Olivenza | 4,113.33 mi (6,619.76 km) |
| West Chicago to Olot | 4,408.04 mi (7,094.05 km) |
| West Chicago to Onate | 4,166.25 mi (6,704.93 km) |
| West Chicago to Onda | 4,374.13 mi (7,039.48 km) |
| West Chicago to Onteniente | 4,402.72 mi (7,085.49 km) |
| West Chicago to Orihuela | 4,415.98 mi (7,106.83 km) |
| West Chicago to Osuna | 4,259.01 mi (6,854.22 km) |
| West Chicago to Ourense | 3,951.42 mi (6,359.20 km) |
| West Chicago to Oviedo | 4,005.89 mi (6,446.86 km) |
| West Chicago to Paiporta | 4,387.80 mi (7,061.49 km) |
| West Chicago to Pajara | 4,162.55 mi (6,698.97 km) |
| West Chicago to Palafolls | 4,439.05 mi (7,143.96 km) |
| West Chicago to Palafrugell | 4,446.93 mi (7,156.64 km) |
| West Chicago to Palamos | 4,448.27 mi (7,158.80 km) |
